Rivastigmine-DHA ion-pair complex improved loading in hybrid nanoparticles for better amyloid inhibition and nose-to-brain targeting in Alzheimer's

Advances in cell-penetrating peptide-based nose-to-brain drug delivery systems

The incidence of brain disorders has gained worldwide attention and the presence of the blood-brain barrier prevents numerous drugs from reaching the targeted brain. The specific physiology of the nasal cavity and the brain provides the feasibility of direct nose-brain delivery, a system that bypasses the blood-brain barrier in a non-invasive manner for brain-targeted drug delivery via intracellular and extracellular mechanisms. The use of CPPs provides further feasibility for naso-brain drug delivery studies, and liposomes, nanopolymer particles, and gels modified with CPPs have demonstrated significant brain-targeting capabilities after nasal delivery. In this paper, the physiology of the nasal cavity and brain, the pathways of naso-brain delivery and the influencing factors are discussed in detail. At the same time, the introduction, classification, mechanism of action and application of CPPs in the nasal-brain delivery system are discussed in detail to provide a theoretical basis for the in-depth study of the application of CPPs in the nasal-brain delivery system.

Advancements in Nanocarrier Systems for Nose-to-Brain Drug Delivery

In recent decades, nose-to-brain drug delivery has shown effectiveness in treating many central nervous system diseases. Intranasally administered drugs can be delivered to the brain through the olfactory and trigeminal pathways that bypass the blood-brain barrier. However, nose-to-brain drug delivery is challenging due to the inadequate nasal mucosa absorption of drugs and the short retention time of the intranasal formulations. These problems can be minimized through the use of nano-drug delivery systems, such as micelles, polymeric nanoparticles, nanoemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers. They can enhance the drug's bioavailability in the brain via increases in drug solubility, permeation, and stability. Nose-to-brain nano-drug delivery systems have been evaluated in vivo by a number of research groups. This review aims to provide an overview of nose-to-brain delivery and recent advances in the development of nano-drug delivery systems for delivering drugs from the nose to the brain to improve the treatment of some central nervous system diseases.

Intranasal Delivery of Paclitaxel-Loaded Ligand Conjugated Polymeric Nanoparticles for Targeted Brain Delivery

Compared to the conventional blood-brain barrier crossing over, nose-to-brain delivery provides a potentially effective substitution, particularly when large molecules of drugs need to be delivered. The majority of macromolecules degrade quickly in a physiological environment. Therefore, drug molecules can be protected against early breakdown by using nanocarrier systems. Targeting nanocarrier system with ligand potential of enhancing bioavailability due to tailored binding affinity to targeting site. In the current study, we prepared paclitaxel (PTX) loaded ascorbic acid (AA) conjugated polycaprolactone (PCL) nanoparticles (NPs) for intranasal administration. Polymeric nanoparticles (PNPs) were prepared using the solvent evaporation method, which was further analyzed for particle size, polydispersity index (PDI), surface charge, encapsulation-efficiency (EE), drug loading (DL), surface morphology, in-vitro drug release, and in-vivo pharmacokinetic evaluation. Results showed the optimized PTX-PNPs showed particle size 114.7 ± 2.96 nm, zeta potential -27.6 ± 1.63 mV, with entrapment efficiency 97.3 ± 0.41%, and drug loading 35.3 ± 0.38%. In-vitro PTX release showed a biphasic release pattern, primary burst release followed by sustained release was observed. An in-vivo pharmacokinetic study showed a 5.6-fold increase in the PTX concentration reaching to the brain. Histopathological results of the nasal mucosa showed minimal alteration after 72 h of administering surface-modified paclitaxel loaded polymeric nanoparticles (AA-PTX-PNPs). Thus, this study highlighted the suitability of a AA-PTX-PNPs as a promising strategy for intranasal administration therapy for various brain disorders.

Development and Characterization of In Situ Gelling Nasal Cilostazol Spanlastics

Cilostazol (CIL), a BCS class II antiplatelet aggregation and vasodilator agent, is used for cerebrovascular diseases to minimize blood-brain barrier dysfunction, white matter-lesion formation, and motor deficits. The current work aimed to develop and optimize cilostazol-loaded spanlastics (CIL-SPA) for nose-to-brain delivery to overcome the low solubility and absorption, the first pass-metabolism, and the adverse effects. The optimal CIL-SPA formulation was loaded into Phytagel® (SPA-PG), Poloxamer-407 (SPA-P407), and chitosan (SPA-CS) gel bases and characterized in terms of colloidal properties, encapsulation efficiency (EE%), mucoadhesive properties, and biopharmaceutical aspects. The developed in situ gelling formulations showed a <300 nm average hydrodynamic diameter, <0.5 polydispersity index, and >|±30| mV zeta potential with a high EE% (>99%). All formulations met the droplet size-distribution criteria of nasal requirements (<200 µm), and all formulations showed adequate mucoadhesion properties. Both the BBB-PAMPA and horizontal permeability study through an artificial membrane revealed that all formulations had higher CIL flux and cumulative permeability at in vitro nose-to-brain conditions compared to the initial CIL. The in vitro drug-release study showed that all formulations released ca. 100% of CIL after 2 h. Therefore, the developed formulations could be promising for improving the low bioavailability of CIL through nose-to-brain delivery.

Development of Thermosensitive Mucoadhesive Gel Based Encapsulated Lipid Microspheres as Nose-to-Brain Rivastigmine Delivery System

Alzheimer's disease (ALZ) is a neurodegenerative disease that damages neuronal cells and causes decline in cognitive abilities. Administration of cholinesterase inhibitor compounds is the primary choice in the treatment of ALZ, one of which is rivastigmine (RVT). Several routes of administration of RVT are available, such as oral and transdermal. However, in the oral route, RVT has low bioavailability, undergoes first-pass metabolism, and the presence of the blood-brain barrier (BBB) reduces the therapeutic concentration of RVT. The transdermal route is nonselective target in the brain. This study aims to combine thermosensitive mucoadhesive gel (TG) and lipid microspheres (LM) as a drug delivery system to improve the efficacy of RVT. Combining these will prevent systemic side effects of RVT and increase drug concentration in the brain. LM was formulated with varying concentrations of Compritol polymer. The results of LM evaluation showed the values of particle size, PDI, and %EE and %DL were 8.519 μm, 0.018 ± 0.004, 72.54%, and 76.43%, respectively. The TG formulation can provide a liquid form at room temperature (25 °C) and a gel at nasal temperature (35 °C). Hemolytic and HET-CAM tests confirmed TG RVT LM's safety for use. Ex vivo studies showed controlled and sustained release of TG RVT LM, and in vivo studies showed TG RVT LM a higher pharmacokinetic profile in the brain than oral formulations and injections. The Cmax was found to be 7.05 ± 0.55 μg/cm3, Tmax was 24 h, and AUC0-24, which is related to the effectiveness of brain targeting, was 225.73 μg/cm3. In conclusion, this study shows the successful development of TG RVT LM, as evidenced by improved drug delivery to the brain, which is characterized by higher concentrations of RVT in the brain compared with oral and injectable RVT, this delivery system shows potential as a future treatment for Alzheimer's disease.

Extracellular nanovesicles as neurotherapeutics for central nervous system disorders

INTRODUCTION

The blood-brain barrier (BBB) is a highly selective structure that protects the central nervous system (CNS) while hindering the delivery of many therapeutic agents. This presents a major challenge in treating neurological disorders, such as multiple sclerosis, where effective drug delivery to the brain is crucial for improving patient outcomes. Innovative strategies are urgently needed to address this limitation.

AREAS COVERED

This review explores the potential of extracellular vesicles (EVs) as innovative drug delivery systems capable of crossing the BBB. EVs are membrane-bound vesicles derived from cells, tissues, or plant materials, offering natural biocompatibility and therapeutic potential. Recent studies investigating the permeability of EVs and their mechanisms for crossing the BBB, such as transcytosis, are summarized. Special emphasis is placed on plant-derived EVs (PDEVs) due to their unique advantages in drug delivery. Challenges related to the large-scale production and therapeutic consistency of EVs are also discussed.

EXPERT OPINION

EVs, particularly PDEVs, hold significant promise as scalable and noninvasive systems for CNS drug delivery. However, critical barriers such as improving standardization techniques, manufacturing processes and addressing scalability must be overcome to facilitate clinical translation. Collaborative efforts in research and innovation will be pivotal in realizing the therapeutic potential of EVs for neurological conditions.

Nanotechnological approaches for efficient N2B delivery: from small-molecule drugs to biopharmaceuticals

Central nervous system diseases negatively affect patients and society. Providing successful noninvasive treatments for these diseases is challenging because of the presence of the blood-brain barrier. While protecting the brain's homeostasis, the barrier limits the passage of almost all large-molecule drugs and most small-molecule drugs. A noninvasive method, nose-to-brain delivery (N2B delivery) has been proposed to overcome this challenge. By exploiting the direct anatomical interaction between the nose and the brain, the drugs can reach the target, the brain. Moreover, the drugs can be encapsulated into various drug delivery systems to enhance physicochemical characteristics and targeting success. Many preclinical data show that this strategy can effectively deliver biopharmaceuticals to the brain. Therefore, this review focuses on N2B delivery while giving examples of different drug delivery systems suitable for the applications. In addition, we emphasize the importance of the effective delivery of monoclonal antibodies and RNA and stress the recent literature tackling this challenge. While giving examples of nanotechnological approaches for the effective delivery of small or large molecules from the current literature, we highlight the preclinical studies and their results to prove the strategies' success and limitations.